timothy_p_mcmahon wrote:3) ἀνθρωπος being the predicate would normally be anarthrous ("God became human" rather than "God became THE [specific] human being")

This is well illustrated in the similar phrase in John 1:14

... ὁ λόγος σὰρξ ἐγένετο ...

Also, I wonder if σημερον works for "on this calendar day in the past", or if it more properly means literally "today". I won't track down all the uses now, but does anyone have a comment on this one way or the other?

And again, there are multiple occurrences of σήμερον in the remainder of this homily.

(For anyone having trouble reading the pseudo-Ath. quotation, a quick crib: I behold a strange mystery: in place of the sun, the Sun of Righteousness making his place, without being circumscribed, in the Virgin. And do not investigate how! For where God wills, the order of nature is overcome. For God willed, was able, descended, saved. Come together, all things! For today the existing and preexisting God becomes what he was not, becomes human, without stepping outside of being God.)

Another little comment: I wondered whether maybe the present tense would be better in the proposed greeting than the aorist. Patristic biblical exposition is I think normally a matter of appropriation and actualization rather than archaeology. But the aorist is used with "today." E.g., again in Chrysostom: